Prior art systems utilize flowing water from dams, called hydroelectric plants, to generate electrical power. Additionally, turbines have been used to convert wind or airflow into electrical power. However, there is a deficiency in utilization of slow moving, underwater current flows, particularly underwater ocean currents.
Velocity is a factor in the amount of hydrokinetic energy that can be extracted from flowing water. Several prior art hydrokinetic electrical generators work in very high velocity or flow environments, such as in the range of 3, 4 or 5 meters per second (about 6, 8 or 10 knots). While these high water velocities offer the potential for the extraction of large amounts of hydrokinetic energy, these velocities are present in a very small percentage of the world's ocean waters.
Flow velocity is only one factor in utilizing hydrokinetic energy. A second factor is the location of useful water currents in the ocean. Open ocean currents usually differ from the ocean floor currents, which, in turn, differ from ocean surface currents. Generally, maximum ocean currents are found near the surface, at relatively shallow depths, and slower moving currents are found near the bottom of the ocean.
Therefore, buoyancy of a hydrokinetic system useful to capture energy from ocean currents is a factor in (a) locating a reasonably optimal depth of operation for the hydrokinetic system; (b) maintaining the depth to achieve an optimal operation; and (c) controlling the pitch, yaw and roll of the system. Further, since the currents in a certain geographic location change over time (daily, monthly or otherwise), a buoyancy and ballast control system for elevation above the ocean floor (depth control) and pitch, yaw and roll control is necessary to effect the extraction of hydrokinetic energy from ocean currents.